Science and Cooking: From Haute Cuisine to Soft Matter Science - Week 4

As I posted in my October 13th blog entry, I've enrolled in an on-line course about the relationship between science and cooking. It's been awhile since my last post about this course, for reasons that may or may not have to do with "Batman: Arkham Origins", and a neglected stack of laundry.

Here's what went down on the fourth week.

• This week the topic is elasticity, and one of the guest lecturers is White House Pastry Chef Bill Yosses.
• Who knew the White House had its own pastry chef? I wonder if either Barrack or Michelle has ever asked him to whip up a batch of cro-nuts for them.
• To measure elasticity, we are shown how it is measured with a spring. This principle of physics, called Hooke's law, states that the force needed to extend or compress a spring by some distance is proportional to that distance. That is, F = k x, where k is a constant factor characteristic of the spring, its stiffness.
• What does this have to do with food? Elasticity in food relates to how it feels in your mouth when you chew it. For example, the elasticity of a steak will increase as it becomes more difficult to chew the longer it is cooked.
• I had no idea there were different mouth feels for tofu, or that firm and soft tofu even existed.
• The mathematical description of an object or substance's tendency to be deformed elastically (i.e., non-permanently) when a force is applied to it is E = U over I³, where U is the interaction energy between the bonds in the material, and I is the distance between them. This is also the equation of the week in case you were wondering.
• We are treated to a scientific look at the making of strudel, which leads to a discussion about gluten, the protein that gives strudel dough its special characteristics.



• Did you know hearing plays a part in the enjoyment of food? Harold McGee talks about an experiment done at Oxford University where the subjects put on sound-blocking headphones, and  sat in front of a microphone, and bit into potato chips. The sound of the biting was picked up by the microphone and processed before the sound was passed back to the eaters' ears through the headphones. When the chewing sound was sent to the headphones unchanged, the eaters rated the chip as normally crisp. When the sound was amplified, they rated the chip as more crisp.
• McGee also mentions anthropologist Richard Wrangham's belief that because cooked food is often easier to chew, the invention of cooking has had a profound effect on the evolution of the human species.
• Dan Souza from America's Test Kitchen and Nathan Myhrvold of Modernist Cuisine fame both recommend slow-roasting tough cuts of meat, like an eye of round roast - who am I to argue?
• Poking your meat full of holes can make it be more juicy. This process is called jaccarding, and is done with a device not surprisingly called a Jaccard. A Jaccard has tiny blades that cuts little bits of the muscle fibers weakening the collagen fibres in them without cutting the meat totally. By poking the meat with holes, the collagen fibers do a less effective job squeezing the moisture out of the meat when it's being cooked.
• Note to self: Invest in a sous-vide machine so I can experience a short rib slow cooked for 72 hours.
• We end Week 4 with a summary of elasticity and another appearance by Bill Yosses, who demonstrates how, with a little sugar, water, and glucose, you can make a candy apple.